1. Field of Invention
The present invention relates to a new apparatus (image sensor apparatus having an additional display device function) that can be used both as an active-matrix-type display device and as an image sensor.
2. Description of Related Art
An active-matrix-type display device in which current-control-type light-emitting elements, such as EL (electroluminescence) elements or LEDs (light-emitting diodes), are used is disclosed in, for example, Japanese Unexamined Patent Publication Nos. 8-54836 and 8-129358. Since any of the light-emitting elements used for this type of display device emits light by itself, there are advantages that, unlike liquid-crystal display devices, it does not require a backlight, and dependence upon viewing angle is small. Meanwhile, as facsimile machines are in the midst of becoming more widespread in ordinary households, there has been a demand for more inexpensive ones as household electrical appliances.
However, since image sensors used in conventional facsimile machines require an optical system, a mechanical system, sensors, an illumination system, and the like, which are expensive, it is difficult to achieve lowering of the price of a facsimile machine.